The
plateau area of Northwestern United States and Southern British Columbia
is generally the region east of the Cascade Mountains and west of the
Continental Divide. The mighty Columbia River and its tributaries dominate
much of this territory. Tribes such as the Kootenai, Kalispel, Okanogan,
Flathead, Spokane, Coeurd’Alene, Yakama, Warm Springs, Umatilla,
Walla Walla, Cayuse and many others, including the Nimiipuu or Nez Perce
Nation live here.